Revolving screen and method of screening.



W. 0. BURCHERDT. REVLVING SCREEN AND MEHO F SCREENING.

3 SHEETSMSHEET I.

IN1/fwn T/Vczler OBO rcherdt BY m WMM ATTORNEYS W. U. BURCHERDT.

REVULVING SCREEN ANU METHOD 0F SCREENING.

APPLncATwN min m1111916.

1 ,2 1 2,1 79. Patented Jan. 16, 1917.

3 SHEETSSHEET 2 /Valer Olorcherdt W. 0. BORCHERDT.

REvoLvsNG scREiN AND MUHUD of SCREENING.

APPUCATUN HLEI) IAN. L 1916.

Patented Jan. 16, 1917.

3 SHEET *SHEET Elv ATTORNEYS UNITED STATES PATENT OFFICE.

WALTER O. BGRCHERDT. OF AUSTNVELLE, VIRGINIA, ASSIGNOR TO THE NEW JERSEY ZINC COMPANY, OF NEW YORK. N. Y.. A COBPRATON OF NEW JERSEY.

REVOLVING SCREEN AND METHD F SCREENING.

Application filed January 7, 1915.

liu it. known that l. Quirico O. llonoiiniarr.y a ultim-n ol' the United States. and a resident` of Austini'illi. in the County ol' lythe and State of Virginia. have invented eert ain new and useful iinproveiuenta in llivolvingi Sri-eens and Methods of Screening: and Vl do hereby deviare the following to he a. l'ull1 cleat'. and exai't deai'ription of the invention. such as will enable otlieri4 Skilled in the art;

. to n'hivh it appertains to niake and use the` an improved construction and operation. and

` a novel methodl of screening of the ore pulp and similar material therewith.

The revolving,r Screen of the present` invention comprises. essentially. a screen vylniler or drinn of suitable screening material. and suitably supported and rotated.y together with means for feedingr to the upper portion of the drum the material to he screened. and one or more Spray derivi-s within the drinn arranged to discharge upn'ardlv' against the srreen at a point beyond that at which the material is fed to the drum.` so that. the mesh of thi` screen ia cleaned and water is re-intz'o- [loved into the material with a further resultingr :svruening atleet.. y

ln describing the novi-l revolvingf :sf-reen of the present; iniention. and the process of erreeningf which is practised therewith, it n ill he assumed that the material to loe ,arreenefl is ore pulp or similar Inni-rial of a liipiid and mobile nature, so that it. can he fed to the srreen in the form of a Subset-.intially uniform or homogeneous fluid orpnlp. although a iletiiiernv in the amenant of water present in .the pulp will he in part reine- (lied duringr the` screening proeese. Sino@ ore pulp4 eonnnoniy contain, insider-able amounts of water'. it will liesi-rihing: the present inventian. that walter is the liquid or fluid which is pria-ent in the adinixtnre with the material to la arreeiied. lt will he understood, however. that other liquide will operate in substantially the sanit- .nanner. and accordingly l eonsidel :sinh liq nids ai; the equivalents of water for pui'poses' Specification of Letters Patent.

ansinned. in def Patented Jan. i6, 1917.

Serial No, 70.807.

:maanpanying drawings. hut` it, is intended and understood that the invention will ho illiiatratiil hy. hat is no1 limited to. the aperilifeuihodiniente` than illustrated and dosvrilwd.

lu thi- .maanpanying drawings. Figure l shows. partly in ventral longitudinal Section and partly in elevation nil; parta liroken anar; a. rovolving, r ,Larven rnilaallvini: the iii-- volition; Fig. L shoiwl the ,aviron in end elevation. with parte` ln'olnu :irfav: like.: in a plan iii-n ot the .ai-reen: Fig AlV ia an enlarged detail sectional View of the screen drain, 'water spray. and feed roogh: Fig. 5 is an enlarged ventral. longitudinal sentier. ol' partis ol' the srreen drinn and inside lioppor; Fig. l shows a niodiiioation of the con atrae-tion of Fig. 4; Fig. 7 shows a further moduli-ation; Fig. 8 shows two i-aereenA arranged for-independent or simultaneous operation; Fig. 9 1s a central section of one of the li airing of Fig. 8; Fig. 10 shows a fin'- tlwr arrangement of two screens; and F ig. 11 shows a stilll further .arran ement. of screens.

The revolving screen il netrated is made up of the circu ar cylinder or drinn l suitably sefured to and supported by th'e Spider or head 2 at one end. The spider is carried by a shaft 3 which turna in bearings 4, and which ia driven by any suitable nie-fins. such as a sprocket` wheel 5, so that the entire drum can be rotated at the flebired speed. The

Screen drain is clamped tqthe head or spider" ln' segmental wooden blcks G and holte '7. The other end of the Screen drinn is stifeneil and heid in its eirenlar shape hy the rings tl and Si suitably, secured together. as h inrets. and 'with the screen bolted to thiL ring hv anni; io.

The Size of the Seremi drinn or .-vlintier can be varied. within rather wide liinits in accord-allee with the quantity' of the material to he eereened, the size of the particles of the material, and other omiditione. When coarse eines of mate 'ials are to he screened, a rraeonaall; heavy wire screen an he used. and u single thickness ol' nerven ma)I snlliee.

.\,'hen. however, tine ezines. ol' material are to he reinovwl. it. in advantageous to Construct the drinn of an outer screen cloth, supported i" and. secured to, an inner framework of h.. v3' efreen cloth, perforated plate. or lattice laire. also in the form of a cylinder. In lii raw., the actual screening surface is snp :aaitat every point hy afrainenork of other.

coarse mesh heavy wire screen cloth, or other supporting material, which provides the requisite mechanical strength and at the same time does not in any way interfere with the passage of the fine ore particles. lhen coni-ser sizes of undersizeprodnct are desired, and a reasonabl heavy wire can be used, it becomes possi le to dispense with the supporting screen as above indicated, and the screening surface then becomes self* supporting. lhether the drum is to be made ot' a single thickness of the screening, or a plurality of thicknesses, will depend upon the diameter and width of the drum', the size of wire used in making the screen, the material to be screened, and other considerations. Since the resistance of-,the drum to deformation from the circular depends upon the friction at the crossing points of the wires in the screen, it is advisable in niost cases to use either brass screen cloth with Athe ioints soldered, or steel wire screen which has been galvanized or welded after weaving, since either treatment effectively prevents relative movement of the wires. Such fabrics are of value particularly' for the inner supporting screen which serves as the support for the outer screen fabric.

The screen drum illustrated in the draw ings is iliade up of an outer screen fabric 11 lof line mesh, and an inner supporting screen of coarser fabric 12, both screens bein suitably attached to the supporting spi er at one end and to the stiilening ring at the Surrounding the lower half of the screen drum, and extending up high enough to catch any splash, is the outside hopper 13, constructed and arranged to catch all material that falls from the screen, and having an outlet l-l suitably arranged to discharge the material to a conveyer or to any other suitable receptacle.

Extending into the open and overhuiig end of the drum is the inside hopper 15. This inside hopper is bolted to and supported by the outer hopper 13 at one end, asindicated at 16, Fig. 2, and t is provided with an outlet trough portion 17 extending outwardly through a hole in the end of the outer hopper. The inner end 19 of the ho per 15 is supported by the end of the sha t 3. By reference to Fig. 5 it will be seen that the end 19 of the hopper has a ring or casting 20 secured thereto by bolts 21, and that this casting or ring is bored to pass over and run upon the inward projection of the shaft 3'whicl1 carries the screen spider the ring 20 being faced to bear against the face of the screen spider hub. By this means the inside hopper is held centrally positioned within the screen drumfand is supported to resist the weight of the material which it receives. The inside hopper, as Well as the outside hopper, are soy shaped as to best fulfil their functions of catching all 4mate- Alarity of the screening rial which passes through the screen cloth, as well as that which falls off the screen cloth. The inside hopper is also constructed so that it will convey the material which passes through the screen toits discharge opening at the overhung end of the drum.

Secured above the screen drum is a feed spout or sole which is adjustable with respectto the drain, and with respect to its4 angle with the horizontal (by means not shown), so that it can be tilted at different angles, and arranged at a hi her or lower position with respect to the rum, de ending upon the character of the material to be fed, and the best position "for the delivery of the material to the screening surface, so that for any given character of material, the best position for the feed of the material to the screening surface can be obtained. The function of the feed s out or sole is to deliver the material to 'e screened, intimately mixed with the water used as a vehicle, against the screening surface in the forni of a sheet of uniform thickness and composition, and at uniform velocity over the whole width of the screening surface. In the apparatus illustrated, the material to be screened is fed from the supply tank or trough 25 to the feed spout or and thence to the screen drum.

Supported within the screen drum, and below the upper portion of the screening surface, are one or more spray pipes, the jets from which are directed upwardly against the screen cloth beyond the point at which the feed Strikes the screen. The function of thesevjets is to clear the holes in the screen fabric which have been Stopped up 'or blanked by particles too large to pass through with the water originally contained in the feed, and to produce an entirely new arrangement of the particles which have deposited on the cloth by the draining away of the original feed water by introducing a fresh amount of the water required as a vehicle, and thus securing, on the now freshl cleaned surface, a secondary screening action. This screening action is very ra id, the water being entirely removed within a short distance and carrying with it the fine material. It is liei-efore possible to place spray pipes as sole 2'6A close together as the distance which the.

screen travels while the water is being rer moved, and thus secure an increase in the screening eflicency for each pipe so added, within the limits set by the increasing angu- Asurface with the horizontal plane which makes it unprofitable to set the pipes lower than a certain point, as will bereadily appreciated.

In Fig. 4 a single spray pipe 27 is shown extending lengthwise within the cylinder beyond the, point at which the material is fed to the screen drum. The

and with the mesh of the ,etlieient screening or long screens is united and discharged together. In this case', the shafts of the screens are parallel, and the drums can he rotated independently when desired. The drums are spaced apart suliiciently to avoid interfer ence andto permit discharge of the. oversize material. These drums are rotated toward each other so that the over'size of both drums is discharged between them. The provision of independent under-size hoppers enables the under-size lfrom the two drums to beseparately collected so that the screens may be operated independently of each other, or operated together, and the undersize from the two screens separately collected. lVhere a series ot' graded products is desired, the screens may readily be arranged to treat the material successively, successive screens increasing or decreasing in size, depending upon whether the' feed to the following screen consists of the over-size or the undersize of the preceding screen. lt is oi course usually desirable to take out the coarser material first` since the tiner screens are thereL by subjected to decreasing quantities of feed.y although this is by no means necessary or i lite of the screen surface. rlhe quantity of water supplied with the feed should bc suilicient to render it perfectly liquid and mobile` although any deficiency in' this direction can be remedied by means of the screening spray. That-is to say, where the feed is not of the proper consistency.l the reintroduction of the water by the spray, and the secoxnlary and further screening etect thus produced,y results in the securing of the desired screening action.

Y 0n the other hand, where the pulps or other materials are very dilute, as is the common condition in mills, the screen ot' the present invention has a wide range ot' application.

The very dilute pulps can be readily handled by properly adjusting the angle ot the the position of the feed spout, with respect to the screen drum. ln connection with the screening of such dilute pulps it may be noted that the screen of the present invention becomes a very effective (ie-wateringmachine when a screen cloth ot suitably fine mesh is used. Thus, when' a Cloth of finer mesh than the particles in the feed is used it is possible to use the screen to de-Water the feed.. vAgain, and

particularly with tailings. it is possible to use the screen to de-water the tailings. and at the same time to remove therefrom the Atine particles of mineral which they usually contain, saving these in the enriched undersized'product for retreatment on a table. The correct size of wire cloth will ot' course be determined by the material to be treated, and the results desired. The ite-introduction t further amounts of water into the material on the screen results in a further wash ing and screening `of this material, in the manner above point/ed out. In mills using a badly screened orclassified feed on jigs, a very important increase in total recovery can be made in this way at very small expense, and at the same time the tailings can' be fle-watered for disposal by conveyor and the waste water recovered for re-use. -Where cle-watering is desiredftogether with removal of the finer particles, should not he used, since these would 1ntroduced water into the tie-watered oversize. At the same time.y itmaybeimportantto provide for cleaning the screen fabric and for removing therefrom the adhering particles. The arrangement of Fig. i' enables this cleaning and removal without again introducing water into the over-size. To this end, a pipe 2T is arranged to discharge its ,iets against the inner side of the upper part of the drum in ad rance of the feed so :that the meshes of the screen will be cleaned,-iind the oversize particles Will fall oli by gra` ity.y while the water will be caught by the inc side hopper.

lt will be seen that the novel revolving screen of the present invention provides 'for the screening and de 'atcringr of pulps and similar materials by subjecting these materials to a primary screening action. and by subserplently spraying water against the screen 11mm-the sido opposite that which receives the material :to-hc screened. so that the water is reintrodiwcd into the material and the pa rticles thereof are rearranged and a further or secondary screening of the. material is effected, lt will also be seen that the novel nnnthod oi screening the orc pulp and similar material. of the present invention` comprisesl a primary screening )y t'ecdinf,lr thc material. ilnimalelv mixed with water. upon the screen, and a subsequent or secondary `screening' by thc rc-introduction of water into the material and the accom panying cleaning of the screen and rearrangement of the particles of the material.

l claim l l. The method of screening ore pulp and similar material, 'which comprises feeding thematerial mixed with water upon the upwardly movingr portion of a rerolving screen and thereby effecting a primary screening of the material and spraying water from below through said screen at a point on the upwardly moving portion ot said screen above the point of feed of the material thereto to reintroduce water into the material and rearrange the particles thereof to effect a further or secondary` screening: ot the material; substantially as described.

Q. The method of screening ore pulp and similar material. which comprises feeding the material mixed with water upon the upwardly moving portion of a revolving the lower sprays screen und thereby effecting n prilmu'y screeninlr of the materiel, spraying water from be ou' through mill srl-reu :it :i point ou the upwardly moving portion of said screen ebow thc point of fred of the )nnteA rial thereto to reintrmluce waiter into the material und rcnrrnnge the particles thereof to effect :l Further or sei-ouml screening of the material, roller-,ting thc liuiteriul which hns passed throughllm screen in a recepliufl'e within smid screen` spraying wnter through seid screen receptacle to remdvc material renmining on seid screen, und collecting the nmtcrial that has failed -to pass 'througlrsaid screen in a receptacle below said screen; substantially us described. i

3. The method of screening orc pulp :md similar material, which comprises feeding' the material mixed with water upon the upwardly moving portions of a revolving screen, spraying Water from below through said screen at a point on theupwurdly movingr portion o-f said sri-een :above the point of feed of the material thereto to reintroduce Water into the material and remfrzinge the particles thereof to effect a further or secondary screening of the nuiterial. collecting the materiel which has passed through the screen ifi a receptacle within said screen and spraying Water through the screen at a point in advance of the point of feed of material theretol and above said receptacle to clean. said screen while permitting the water to flow into said receptacle.; substsntially as described.

4. The method of screening orc pulp and similar material, which comprises feeding the material mixed with water upon the upwardly moving portion of a revolving screen and thereby electing a. primary screenin from be ow through said screen at a point on the upwardly moving portion of said screen above the poin't of feed of the mate rial thereto to reintroduce Water into thc material and rearrange the particles thereof to effect a further or secondary screening of the material, collecting the material which has passed through the screen in a receptacle Within said screen, spraying Water throughsaid screenata point `below vseid receptacle-to remove material remainingI on said screen, collecting the material that has failedfto pass through said screen in a receptacle below seid screen, and sprzyying water through the screen at a point in advance of the point of feed. of material thereto and above said receptacle within the screen to clean said screen while permitting the weten to flow into said receptafcle; substantially as described. i

5. A revolving screen for ore pulp and similar material, comprising a screen drum, means for rotating said drum, means for at a point below saidv of the material, spraying v'ater.

feedin the material to be screened on the upwau'( ly moving portion of the drum and one or more spraying` devices within the" drum dischurgm through the u wurdly moving portion of said drum above tlie oint of feed of the material thereto, Where y a further or secondary screening of material is ell'ectcd; `substantially as described.

(l. A revolving screen for ore pulp andl similar material, comprisin a screen drum, means 'for rotating seid rum, means for feeding the material to be screened on the upwardly moving portion of the drum and one or more spraying devices within the drum dischurgmg through the u wardly moving portion of Said drum above tie oint of feed of the material thereto, Where y a further or secondary screening of material is effected, means within the drum for collecting the material which has passed through the Screen, und one or more spraying devices within the drum disclmrging throu h the same below seid collecting means, w ereb the material that has failed to pass throug said screen is removed therefrom; substantinlly :is described.

7. A revolving screen for ore pulp and similar material, comprising n screen drum, means for rotatin said drum, means for feeding the material to be screened on the upwardly moving portion of the drum, one or more spraying devices within the drum discharging through the upwardly movin portion of said drum above the oint of fee of the material thereto, where a further or secondary screening of material is effected, means within the drum for collecting the material which has passed through the screen, one or more spraying devices within the drum discharging through,the same below said collectio means, whereby the materia-l that has fai ed to ass through said screen is removed there rom, and one or more spraying devices within the drum dischargin through the same et a point in advance o? the point of feed of materiel there to and above said collecting means for cleaning said screen while permittin water to flow lnto seid collecting means; su stnntiall-y' as described.

8. A revolving screen 4for ore pulp and similar materiahcomprising a screen drum, means for rotatin said drum, means for feedin the material to be screened on the upwar ly moving portion of thev drum, one or more spraying devices within the drum discharging-through the upwardly moving portion of said drum above the oint of feed of the material thereto; where y a further terial thereto and above said collecting outside the drum arranged to catch the ma means-for cleaning said screen while permitterial passing through the screen and the ting the Water to flow into said co lecting oversize therefrom res ectvely, and 'a means; substantially as described. Aspra ing device within tide drum arranged 9. A revolving screen for ore pulp. and to discharge against the screen in advance similar material, comprisin ascreen drum, of the point of feed of the material thereto means for rotating said rum, means for and at a point above the inside hopper, feeding the material to be screened on the whereby the screen is cleaned by said sprayupwardly movingv portion of the drum and ing device and the water is caught by the one or more spraying devices within the inside hopper; substantially as described. drum dischargin through the u Wa'rdly 12. A revolving screen for ore pulp and moving portiono said drum abovet e oint similar inateriah'comprising an ovcrhung of feed of the material thereto, where y a screen drum having a supporting head or i 'further' or secondary screening of material spider at one end and being openv at the is effected, means within the um for colother, means for rotating said drum, means '70 lecting the material which has passed for feeding upon the upwardly moving porthrough the screen, and one or more spraytion of said drum the material to be ingA devices within the drum discharging screened and one or more spraying devices through the same below said collecting extending into the open end of said drum, -meanswhereby the material that has failed arranged to discharge through the upto pass through said screen is removed therewardly moving portion of said screen above `from,qand means below said drum for colthe point of feed of the material thereto,

scribed.

lecting the material that `has failedto pass whereby a further or secondary screening through said screen; substantially as deof the material is effected.; substantially as i i described.

10. ,A revolving screen for ore pulp and 13. Aii apparatus for screening ore pulp similar material, comprising an overhang and similar material comprising a shaft, screen drum having a supporting head or driving means for said shaft, a sleeve sur- 'spiderat one end,a shaft earryingsaid head rounding each end of said shaft, clutch or spidermeans for rotating the shaft and mechanism associated with each of .said 85 drum,V means for feeding to the upwar ly sleeves for connecting them to said shaft at moving portion of the drum the material will, a bearing for each sleeve, a spider conto be screened, an outside' hopper inclosing iiected to each sleeve, a screen drii'm conthe lowerportion of the drum and arranged nected to and supported by each. spider,

. to `catch the .oversize therefrom, an n.' de means for feeding upon the upwardly mov- 901' hopper within the drum arranged to c eh ing` portions of said drums the material to the material passing 4thr'ough the screen, iid b screened and one or more spraying deinside hopper being secured to and supi rtvices extending into the open end of each ed by the side wall of theoutside hoppf at drum, arranged to discharge through the its outer end and having a discharge po ion upwardly moving portions of said screens 9a extending through said' side Wall, and said aoove the points of feed of material thereto, inside hopper bein supported at its inner whereby a further or secondary screening of end upon the end o the shaft; substantially the material is effected. as described. A 14. An apparatus for screening ore nlp 11. A revolving screen for ore pulp and and similar material, comprising a s aft, similar material, eomprisinga screen drum, a spider mounted upon an end of said shaft, means for rotating said drumymeans for a screen drum composed ofA an inner supfeeding to the upwardly moving portion of portingr screen of relatively coarse mesh an4 the drum-the material to be screened, and an outer screen of relatively fine mesh, one or more spraying devices within the means for attaching said drum to said 105 drum arranged to discharge through the upspider and means attached to the outer enge wardly moving portion of the screen above of said drinn for stiffening the same an the -point of eed of the-material thereto, holding it in circular shape. whereby a further or secondary screening of In testimony whereof I aix my si atiire. the material is effected, hoppers inside and WALTER 0. BORCHE DT. 

